Field of the Invention
Our invention generally relates to a thermoplastic bottle onto which a structure is crimped, and a method of manufacturing a thermoplastic bottle that includes crimping a structure to the bottle. More specifically, our invention relates to a thermoplastic bottle that includes protrusions extending from a flange adjacent to one end of the bottle, with the protrusions providing for an interference fit with a valve cup prior to the valve cup being crimped to the flange.
Related Art
Systems that are used to dispense liquid and/or gaseous products from a container such as a bottle, and in particular, in systems that are used to dispense aerosol products, a valve mechanism is used to allow selected release of the product from the bottle. The valve mechanism is usually a separately manufactured structure that is attached to the bottle after the bottle structure itself is manufactured. Often, the valve structure includes a valve cup as the portion that is physically attached to the bottle, with the valve cup positioned adjacent to an open end of the bottle. An example of such a valve cup can be seen in U.S. Pat. No. 4,730,752, which is hereby incorporated by reference in its entirety.
To attach a valve cup to a bottle, the valve cup can be crimped to a portion of the bottle such as an annular ring that is provided adjacent to an open end of the bottle. The aforementioned U.S. Pat. No. 4,730,752 demonstrates crimping of a valve cup to a bottle. The crimping attachment of a valve cup is usually performed in a two-step process. First, the valve cup is set onto the bottle at one location, in a manufacturing line. The bottle and set valve cup are then moved to a crimping station at another location in the manufacturing line, where the valve cup is crimped to the bottle structure.
Because the setting of the valve cup onto the bottle and the crimping of the valve cup to the bottle ore separate steps, and because the bottle with the set, but not crimped, valve cup is often moved before the crimping operation, a problem sometimes arises in that the valve cup may shift from is initially-set position before the crimping operation occurs, in general the tolerance in the positioning of the valve cup that allows for a successful crimping operation is very small, sometimes on the order of thousandths of an inch. Thus, even a small shift in the valve cup can greatly reduce the effectiveness of the crimped connection between the valve cup and bottle. For aerosol products, when the bottle with an ineffectively crimped valve cup is pressurized, the valve cup can sometimes be completely blown off of the bottle. In less extreme examples, poorly crimped valve cups may allow product to leak from, the bottle.
To stabilize a set, but not crimped, valve cup to a bottle, dimples are sometimes added to the portion of the valve cup that contacts the bottle. The dimples can effectively hold the valve cup in place before the crimping operation, particularly when the bottle is made from a metallic material. Further, the dimples do not damage the relatively-strong metallic bottle structure when the valve cup is crimped.
There is an increasing interest, however, in the use of thermoplastic bottles that dispense aerosol products. As compared to metallic bottles, thermoplastic bottles provide greater flexibly in terms of manufacturing and aesthetic design, recyclability, and thermoplastic bottles are potentially less expensive than metallic bottles. When a valve cup that includes dimples in its crimping portion is crimped to a thermoplastic bottle, the dimples create high stress on the portions of the plastic bottle structure that are contacted by the dimples after crimping. The stress created by the dimples can sometimes crack the thermoplastic bottle structure, rendering the thermoplastic bottle useless for dispensing pressurized products, such as aerosol compositions.